One of the most important qualities of chewing gum is the texture or softness of the gum both before chewing and during chewing. Desirable gums should have a texture which is neither too soft nor too hard.
The texture of chewing gum may be modified by the addition of certain flavors which act as plasticizers to increase gum softness. For example, peppermint oil flavors are known to exhibit plasticizing properties when added to the gum base in the chewing gum making process. A level as low as 1% of peppermint oil in the chewing gum results in noticeable softening of the chewing gum and the bolus. Moreover, other flavors, such as spearmint, mixed fruit flavors and fruit flavors including cherry, orange, lemon and the like also plasticize or soften the chewing gum at normal use levels of 1 to 2% in the chewing gum, but the softening effect is not lasting during storange or chewing. These flavors tend to migrate to the water-soluble phase in the chewing gum and are consumed almost immediately. It is impractical to increase the level of flavor to higher concentrations because of excessive plasticizing action resulting in sloppy chews and unacceptable organoleptic qualities.